<template>
    <div class="app-container">
        <h2 style="text-align: center;">发布新课程</h2>
        <el-steps :active="1" process-status="wait" align-center style="marginbottom: 40px;">
            <el-step title="填写课程基本信息"/>
            <el-step title="创建课程大纲"/>
            <el-step title="提交审核"/>
        </el-steps>
        <el-form label-width="120px">
            <el-form-item label="课程标题">
                <el-input v-model="courseInfo.title" placeholder=" 示例：机器学习项目课：从基础到搭建项目视频课程。专业名称注意大小写"/>
            </el-form-item>

            <!-- 所属分类 TODO -->
            <el-form-item label="课程分类">
                <!-- 一级分类 -->
                <el-select
                    v-model="courseInfo.subjectParentId"
                    placeholder="一级分类" @change="subjectLevelOneChanged">
                    <el-option
                        v-for="subject in subjectOneList"
                        :key="subject.id"
                        :label="subject.title"
                        :value="subject.id"/>
                </el-select>

                <!-- 二级分类 -->
                <el-select
                    v-model="courseInfo.subjectId"
                    placeholder="二级分类">
                    <el-option
                        v-for="subject in subjectTwoList"
                        :key="subject.id"
                        :label="subject.title"
                        :value="subject.id"/>
                </el-select>

            </el-form-item>

            <!-- 课程讲师 -->
            <el-form-item label="课程讲师">
                <el-select
                    v-model="courseInfo.teacherId"
                    placeholder="请选择">
                    <el-option
                        v-for="teacher in teacherList"
                        :key="teacher.id"
                        :label="teacher.name"
                        :value="teacher.id"/>
                </el-select>
            </el-form-item>

            <el-form-item label="总课时">
                <el-input-number :min="0" v-model="courseInfo.lessonNum" controls-position="right" placeholder="数"/>
            </el-form-item>
            <!-- 课程简介 TODO -->
            <el-form-item label="课程简介">
                <tinymce v-model="courseInfo.description" placeholder=""/>
            </el-form-item>

            <!-- 课程封面 -->
            <el-form-item label="课程封面">

                <el-upload
                    :show-file-list="false"
                    :on-success="handleAvatarSuccess"
                    :before-upload="beforeAvatarUpload"
                    :action="BASE_API+'/eduoss/fileoss'"
                    class="avatar-uploader">
                    <img :src="courseInfo.cover">
                </el-upload>

            </el-form-item>

            <el-form-item label="课程价格">
                <el-input-number :min="0" v-model="courseInfo.price" controls-position="right" placeholder=""/>
            </el-form-item>
            <el-form-item>
                <el-button :disabled="saveBtnDisabled" type="primary" @click="saveOrUpdate">保存并下一步</el-button>
            </el-form-item>
        </el-form>
    </div>
</template>
<script>
import course from '@/api/edu/course'
import subject from '@/api/edu/subject'
import Tinymce from '@/components/Tinymce'

export default {
    components: {Tinymce},//声明组件
    data() {
        return {
            saveBtnDisabled:false,
            courseInfo:{
                title: '',
                subjectId: '',
                subjectParentId:'',
                teacherId: '',
                lessonNum: 0,
                description: '',
                cover: 'https://edu-1010lj.oss-cn-chengdu.aliyuncs.com/6.jpg',
                price: 0
            },
            BASE_API: process.env.BASE_API,//接口API地址
            teacherList:[],//封装所有讲师
            subjectOneList:[],//所有一级分类
            subjectTwoList:[],//所有二级分类
            courseId:''//课程id
        }
    },
    created() {
        this.init()
        // this.courseInfo.lessonNum=0
        // this.courseInfo.price=0
    },
    watch: {
        $route(to,from){ //路由变化方式，路由发生变化，方法就会执行,解决已在当前页面，再点添加数据不改变的bug
            this.init()
        }
    },
    methods:{
        init(){
            //获取路由id
            if(this.$route.params && this.$route.params.id){
                this.courseId=this.$route.params.id
                //根据id查询课程
                this.getInfo()
            }else{
                this.courseInfo={}
                this.courseInfo.cover='https://edu-1010lj.oss-cn-chengdu.aliyuncs.com/6.jpg'
                //获取所有讲师
                this.getListTeacher()
                this.getOneSubjectList()
            }
        },
        //根据id查询
        getInfo(){
            course.getCourseInfoId(this.courseId)
                .then(response => {
                    this.courseInfo=response.data.courseInfoVo
                    //查询所有分类，包含一级二级的树型结构
                    subject.getSubjectList()
                        .then(response => {
                            //获取一级
                            this.subjectOneList=response.data.list
                            //获取二级
                            for(let oneSubject of this.subjectOneList){
                                if(this.courseInfo.subjectParentId == oneSubject.id){
                                    this.subjectTwoList=oneSubject.children
                                }
                            }
                        })
                        //初始化所有讲师
                        this.getListTeacher()
                })
        },
        //封面上传成功
        handleAvatarSuccess(res,file){
            this.courseInfo.cover = res.data.url
        },
        //封面上传之前
        beforeAvatarUpload(file){
            const isJPG = file.type === 'image/jpeg'
            const isLt2M = file.size / 1024 /1024 <2 //图片大小是否小于2M
            if(!isJPG){
                this.$message.error('上传头像图片只能是 JPG 格式！')
            }
            if(!isLt2M){
                this.$message.error('上传头像图片大小不能超过 2MB')
            }
            return isJPG && isLt2M
        },
        subjectLevelOneChanged(value){//value为option子标签属性 :value 的值
            //从后端获取的subjectOneList是树形结构，包含一级二级分类
            for(let subjectOne of this.subjectOneList){
                if(subjectOne.id == value){
                    this.subjectTwoList = subjectOne.children
                    //清空二级id
                    this.courseInfo.subjectId='';
                }
            }
        },
        //查询所有一级分类
        getOneSubjectList(){
            subject.getSubjectList()
                .then(response => {
                    this.subjectOneList = response.data.list
                })
        },
        //查询所有讲师
        getListTeacher(){
            course.getListTeacher()
                .then(response => {
                    this.teacherList = response.data.items
                })
        },
        //添加课程
        addCourse(){
            course.addCourseInfo(this.courseInfo)
                .then(response => {
                    //提示
                    this.$message({
                        type: 'success',
                        message: '添加课程信息成功'
                    })
                    //跳转到第二步
                    this.$router.push({path:'/course/chapter/'+response.data.courseId})
                })
        },
        //修改课程
        updateCourse(){
            course.updateCourseInfoId(this.courseInfo)
                .then(response => {
                    //提示
                    this.$message({
                        type: 'success',
                        message: '修改课程信息成功'
                    })
                    //跳转到第二步
                    this.$router.push({path:'/course/chapter/'+this.courseId})
                })
        },
        saveOrUpdate() {
            //根据courseInfo.id是否有值判断是添加还是修改
            if(this.courseInfo.id){
                this.updateCourse()
            }else{
                this.addCourse()
            }
        }
    }
}
</script>
<!-- scoped表示样式只在当前页面生效 -->
<style scoped>
.tinymce-container {
    line-height: 29px;
}
</style>